管道离心风机

近年来,我们设计并试制成功了一种特殊的风机——管道离心风机,它不同于普通离心风机,没有蜗壳,其进气、出气也不像普通离心风机那样互成90°角,而是在同一轴线上。但它也区别于轴流风机,其工作特性却与离心风机相同,比较稳定。由于气流的进、出口是在同一轴线上,无需像普通带蜗壳的离心风机那样与之相连接的风管需转弯,因此,安装十分简便,占用空间极小,如图1所示。空气在普通离心风机内流动时,其能量的变换系由转轴将机械功传给叶轮内的空气,变为静压力及速度能,经过断面渐大的蜗壳,将一部分速度能转变为压力能,以提高空气离开蜗壳时的静压力。这就是说,空气在离心风机内有两次能量变换。空气在叶轮中所增加的静压     

无蜗壳离心通风机特性及其在空调领域的应用

无蜗壳风机作为一种新形式的风机技术,在组合式空调机组中的应用日趋广泛。特别是大风量的组合式空调机组采用多台无蜗壳风机并联工作,通过控制风机开启台数以调节风量,具有很大的节能优势。     

多翼离心风机蜗壳内整流破涡的研究

对双吸式多翼离心风机进行三维数值模拟,分析蜗壳内部气流组织的演化过程,以及蜗壳、集流器形状,叶轮出流、蜗壳回流气流对气流组织的影响,利用三维流线分析的方法探究了双吸式多翼离心风机蜗舌附近旋涡区产生的机理。在此基础上,在蜗壳180°至270°区域壁面设置整流破涡装置,并对装置的3个尺寸参数进行正交实验。结果表明,优选方案有效破碎蜗壳内大尺度涡旋,并通过影响蜗壳内气流组织,削弱出口回流范围及强度。各工况下整流前后Ps-Qv及η-Qv性能曲线对比表明,整流后流量大于10.58 m~3/min时,出口静压提升明显,风机高效区得到拓宽。     

无蜗壳风机空气动力性能解读及其应用

介绍了无蜗壳风机与常用有蜗壳风机之间的结构差异、性能测试方法与性能计算的区别。通过性能试验发现,无蜗壳风机配置在空调机组内时,不同于有蜗壳风机可直接按其名义风量、压力选取,两者存在一定的差异。以对无蜗壳风机的理解和试验结果为基础,对风机室的设计提出了相应建议。认为使用无蜗壳风机时,必须配置风机室,尽量采用该风机性能曲线的中段区域参数。     

模块式送回风机的研制与应用

本文分析并研究了国内市场主流组合式中央空调空气处理器送、回风机段结构的缺陷，提出了“无蜗壳模块式系统“的设计理念，并且阐述了在大型计算机流体动力模拟软件辅助下设计研制而成的装有无蜗壳风机的新型模块式遥回风机段的价值和推广意义。     

现行国家建筑标准设计图总目录(2000年)Ⅷ

结构专业（二）备注１９７８１９８３１９８７１９８９１９８８１９８７１９９２１９９０１９９０编制日期图集主要内容基本风压≤５００Ｎ／ｍ２,抗震设防烈度７、８度绑扎骨架 ,跨度４．２～６．６ｍ用橡胶隔振器隔振序图图集名称钢筋混凝土折线形屋架钢筋混凝土折线形屋架４ -７２ -１１,Ｂ４ -７２ -１１型离心通风机钢架隔振台座用Ｊ１ 型金属弹簧减振器隔振 ,供施工单位使用Ｊ２１、Ｊ２３系列压力机钢筋混凝土隔振台座用振橡胶隔振器隔振序号多级离心泵混凝土隔振台座预应力钢筋混凝土工字形屋面梁预应力钢筋混凝土工字形屋面梁预应…     

DF系列高效、变速、低噪声离心通风机——余姚通用机器厂产品简介

我厂生产有各种型式的前向多翼型DF系列离心通风机,该产品是参照国内外各类低噪声风机的优点而设计、研制的高效、变速、低噪声离心通风机。其特点是双进风,体积小,风量大,调节方     

无蜗壳风机的特性研究

实验表明,自制叶轮的性能已达国外同类产品的性能水平。分析了影响无蜗壳风机性能的多种因素,探索了无蜗壳风机的使用条件及其应用于空调箱的可行性。     

扫路车用离心风机叶轮内流仿真及优化设计研究

以某型扫路车用离心风机为研究对象，利用数值仿真方法分析了扫路车用离心风机叶轮流道内部涡系结构、压力分布、涡量分布和熵值分布特征等，根据仿真结果提出了叶轮优化设计改进方向，并与试验结果进行了对比分析，验证了此方法的有效性，为扫路车用离心风机叶轮优化设计提供了一种新方法。     

基于离心风机内流场数值分析的优化设计

本文以某型离心风机为研究对象,对其前弯叶片进行修改,采用CFD商用软件Fluent14.0进行三维实体建模,了解其内部流场、压力场等,依据这些信息对叶轮进行优化设计。最后通过制作样机进行试验验证,得到满足大吨位扫路车性能需求的改良风机。     

Numerical simulation on the temperature field in an equipment cabin of a high-speed railway train

With train speed increasing, the heat generation from its key equipment is growing as well and the cooling and ventilation of the equipment cabin become more and more important. In this paper, computational fluid dynamics (CFD) method is adopted to simulate the airflow and the temperature field in indoor and outdoor space of the equipment cabin when the train moves at 250 km/h in open space. The simulation results indicate that the surface temperature of the main heat generation equipment is not beyond the limit. When the train moves forward and backward, the maximum average surface temperature of the heat generation equipment is 56.5 °C and 71.7 °C, respectively, and the airflow rates of the fans in the equipment cabin are decreased by 9.1% and 5.2%, if compared to the rated value, respectively. Both forward and backward running conditions should be considered when designing the layout of the equipment and grilles. It is suggested that, the major heat generation equipment should be located in the middle of the cabin; the flow rate decrement of the cooling fan when the train moves at 250 km/h should be taken into account.     

浅谈民用建筑中风机的选择及运行

论述了风机的工作原理和几个重要参数及其特性曲线,就如何选择风机,阐述了近年来民用建筑中常用风机的种类、型号、特点以及风机的运行调试等问题,指出选择风机时应综合考虑各方面因素,以期帮助民用建筑施工中正确选择、使用风机。     

某型混流风机损坏原因浅探

根据离心风机与混流风机运行特性的区别,分析了混流风机运行中的各种受限因素,指出了喘振是造成混流风机损坏的最直接原因,提出了在空调工程中应慎用混流风机的观点。     

The Use of Positive Pressure Ventilation Fans During Firefighting Operations in Underground Stations: An Experimental Study

Positive pressure ventilation (PPV) fans are widely used by the fire service during firefighting operations in buildings. Fans are positioned to create a flow through the enclosure. This flow can remove the smoke after the fire or affect the direction of the smoke to support firefighting operations. In subway stations, it is less common to use PPV fans. Here, 106 full-scale tests with up to four fans have been performed in a training building that represents a subway station. The fans were used as extraction fans. The generated flow through the subway station has been measured. The critical velocity for a hypothetical tunnel (W × H: 3.17 × 4.15 m) attached to the subway station has been calculated as 2.37 m/s. Reaching the critical velocity has been used as criterion for ‘success’. All combinations with four fans exceed this velocity, supporting the idea that the fans could be used to facilitate a firefighting operation. The location of the fans was varied. Combinations with three fans on the platform and one at the top of the staircase performed better than combinations with two fans on the platform, one on the landing and one at the top of the staircase. There is an optimum value for the distance between the fans on the platform and the first step of the staircase. This value depends on the angle of inclination of the fans. The fans were not capable of creating a flow that exceeded the critical velocity in the station itself (L × W × H: 60 × 7.15 × 4.53 m). However, a velocity of 2.40 m/s corresponds to a flow rate that will limit the backlayering distance in the station to 15 m. This was only achieved by tests with four fans (three on the platform and one at the top of the staircase).     

Computational study of effects of jet fans on the ventilation of a highway curved tunnel

A computational study was carried out to investigate the aerodynamic behavior of jet fans in a curved road tunnel and its effects on the tunnel ventilation system. It has been found that the variations of the static and dynamic pressure in a curved tunnel are non-monotonic. After the issue of the jets, the pressure initially increases gradually, but this is followed by a sudden drop and then a recovery. This is attributed to the interaction between the jets and the curved walls of the tunnel. A sudden increase in pressure is resulted as the jet reaches the convex wall, whereas that the concave wall is approached causes a pressure reduction. The flow becomes asymmetrical downstream of the jets. The development of the jets depends on the separation of the fans and the distance between the fans and the tunnel walls. Increasing the space between the fans or moving them away from the tunnel ceiling makes the jets spreading more quickly across the cross-section. However, it takes a longer distance for the jets to develop when the fans are close to each other or to the tunnel wall. The distance required for pressure to be fully recovered is approximately 90–120 m in this study. The biggest pressure-rising coefficient is obtained when the fans are arranged according to the distance of 2.4 m between the fans, the fans offset of 0.5 m from the centre line towards the convex wall, and the ratio of the distance between fans and the ceiling to the diameter of fans of 1.77.     

A study of the effectiveness of mechanical ventilation systems of a hawker center in Singapore using CFD simulations

A two interlinked approach was utilized to investigate the effectiveness of mechanical ventilation systems of a hawker center in Singapore. Field measurements and thermal comfort survey were conducted to evaluate the thermal comfort perceptions of the users of the hawker center, and the areas with poor thermal comfort conditions were identified. The CFD simulations were conducted to study the impact on thermal comfort of three kinds of fans (wall fans, ceiling fans and extract fans) and to determine the type of the fan which could improve the thermal conditions more effectively in the hawker center.     

Modelling of the coefficient of performance of an air-cooled screw chiller with variable speed condenser fans

Air-cooled chillers are generally recognized as energy intensive equipment in air-conditioned buildings in the subtropical climate. This paper considers how the use of variable speed condenser fans enables these chillers to operate more efficiently. The thermodynamic model of an air-cooled screw chiller was developed using the simulation program TRNSYS and validated using the field data and specifications of the chiller. The staging of condenser fans and the control of their speed in various operating conditions were described. A comparison was made on the coefficient of performance of the chiller in the steady state with various control strategies: head pressure control with constant or variable speed condenser fans; condensing temperature control (CTC) with constant or variable speed condenser fans. Potential improvements in the chiller COP due to the use of CTC with variable speed condenser fans were discussed. The findings of this paper are useful in developing more energy efficient air-cooled chillers.     

浅析地铁隧道风机的配电及控制方案

从地铁隧道风机的配电及控制两个环节入手,结合隧道风机功率大,布置形式多样的特点,介绍了地铁隧道风机配电及控制方案的选择。     

直接空冷系统风机运行扰力试验研究

采用1∶1试验模型,运用应变片组合的方法对风机运行对支撑结构产生的扰力进行测试。测试结果表明,风机运行时不仅因转子的偏心产生径向离心力,还因叶片竖向振动产生弯矩和因驱动叶片转动产生扭矩,依据现有的设计标准求得的扰力类型和取值与试验结果相差都较大,现有的标准不适用于这种大直径的风机设备。建议对于大直径空冷风机设备,其扰力的取值应单独制定扰力取值标准。试验结果有助于推进直接空冷系统的结构设计自主化进程。     

消防排烟风机、正压风机控制电路优化

根据现行消防规范,对消防排烟风机、正压风机控制电路进行了优化,以提高系统的可靠性。